drivers/crypto/ccp/ccp-crypto-aes-xts.c

   1 /*
   2  * AMD Cryptographic Coprocessor (CCP) AES XTS crypto API support
   3  *
   4  * Copyright (C) 2013 Advanced Micro Devices, Inc.
   5  *
   6  * Author: Tom Lendacky <thomas.lendacky@amd.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/sched.h>
  15 #include <linux/delay.h>
  16 #include <linux/scatterlist.h>
  17 #include <linux/crypto.h>
  18 #include <crypto/algapi.h>
  19 #include <crypto/aes.h>
  20 #include <crypto/scatterwalk.h>
  21
  22 #include "ccp-crypto.h"
  23
  24
  25 struct ccp_aes_xts_def {
  26         const char *name;
  27         const char *drv_name;
  28 };
  29
  30 static struct ccp_aes_xts_def aes_xts_algs[] = {
  31         {
  32                 .name           = "xts(aes)",
  33                 .drv_name       = "xts-aes-ccp",
  34         },
  35 };
  36
  37 struct ccp_unit_size_map {
  38         unsigned int size;
  39         u32 value;
  40 };
  41
  42 static struct ccp_unit_size_map unit_size_map[] = {
  43         {
  44                 .size   = 4096,
  45                 .value  = CCP_XTS_AES_UNIT_SIZE_4096,
  46         },
  47         {
  48                 .size   = 2048,
  49                 .value  = CCP_XTS_AES_UNIT_SIZE_2048,
  50         },
  51         {
  52                 .size   = 1024,
  53                 .value  = CCP_XTS_AES_UNIT_SIZE_1024,
  54         },
  55         {
  56                 .size   = 512,
  57                 .value  = CCP_XTS_AES_UNIT_SIZE_512,
  58         },
  59         {
  60                 .size   = 256,
  61                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  62         },
  63         {
  64                 .size   = 128,
  65                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  66         },
  67         {
  68                 .size   = 64,
  69                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  70         },
  71         {
  72                 .size   = 32,
  73                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  74         },
  75         {
  76                 .size   = 16,
  77                 .value  = CCP_XTS_AES_UNIT_SIZE_16,
  78         },
  79         {
  80                 .size   = 1,
  81                 .value  = CCP_XTS_AES_UNIT_SIZE__LAST,
  82         },
  83 };
  84
  85 static int ccp_aes_xts_complete(struct crypto_async_request *async_req, int ret)
  86 {
  87         struct ablkcipher_request *req = ablkcipher_request_cast(async_req);
  88         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
  89
  90         if (ret)
  91                 return ret;
  92
  93         memcpy(req->info, rctx->iv, AES_BLOCK_SIZE);
  94
  95         return 0;
  96 }
  97
  98 static int ccp_aes_xts_setkey(struct crypto_ablkcipher *tfm, const u8 *key,
  99                               unsigned int key_len)
 100 {
 101         struct ccp_ctx *ctx = crypto_tfm_ctx(crypto_ablkcipher_tfm(tfm));
 102
 103         /* Only support 128-bit AES key with a 128-bit Tweak key,
 104          * otherwise use the fallback
 105          */
 106         switch (key_len) {
 107         case AES_KEYSIZE_128 * 2:
 108                 memcpy(ctx->u.aes.key, key, key_len);
 109                 break;
 110         }
 111         ctx->u.aes.key_len = key_len / 2;
 112         sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);
 113
 114         return crypto_ablkcipher_setkey(ctx->u.aes.tfm_ablkcipher, key,
 115                                         key_len);
 116 }
 117
 118 static int ccp_aes_xts_crypt(struct ablkcipher_request *req,
 119                              unsigned int encrypt)
 120 {
 121         struct crypto_tfm *tfm =
 122                 crypto_ablkcipher_tfm(crypto_ablkcipher_reqtfm(req));
 123         struct ccp_ctx *ctx = crypto_tfm_ctx(req->base.tfm);
 124         struct ccp_aes_req_ctx *rctx = ablkcipher_request_ctx(req);
 125         unsigned int unit;
 126         int ret;
 127
 128         if (!ctx->u.aes.key_len)
 129                 return -EINVAL;
 130
 131         if (req->nbytes & (AES_BLOCK_SIZE - 1))
 132                 return -EINVAL;
 133
 134         if (!req->info)
 135                 return -EINVAL;
 136
 137         for (unit = 0; unit < ARRAY_SIZE(unit_size_map); unit++)
 138                 if (!(req->nbytes & (unit_size_map[unit].size - 1)))
 139                         break;
 140
 141         if ((unit_size_map[unit].value == CCP_XTS_AES_UNIT_SIZE__LAST) ||
 142             (ctx->u.aes.key_len != AES_KEYSIZE_128)) {
 143                 /* Use the fallback to process the request for any
 144                  * unsupported unit sizes or key sizes
 145                  */
 146                 ablkcipher_request_set_tfm(req, ctx->u.aes.tfm_ablkcipher);
 147                 ret = (encrypt) ? crypto_ablkcipher_encrypt(req) :
 148                                   crypto_ablkcipher_decrypt(req);
 149                 ablkcipher_request_set_tfm(req, __crypto_ablkcipher_cast(tfm));
 150
 151                 return ret;
 152         }
 153
 154         memcpy(rctx->iv, req->info, AES_BLOCK_SIZE);
 155         sg_init_one(&rctx->iv_sg, rctx->iv, AES_BLOCK_SIZE);
 156
 157         memset(&rctx->cmd, 0, sizeof(rctx->cmd));
 158         INIT_LIST_HEAD(&rctx->cmd.entry);
 159         rctx->cmd.engine = CCP_ENGINE_XTS_AES_128;
 160         rctx->cmd.u.xts.action = (encrypt) ? CCP_AES_ACTION_ENCRYPT
 161                                            : CCP_AES_ACTION_DECRYPT;
 162         rctx->cmd.u.xts.unit_size = unit_size_map[unit].value;
 163         rctx->cmd.u.xts.key = &ctx->u.aes.key_sg;
 164         rctx->cmd.u.xts.key_len = ctx->u.aes.key_len;
 165         rctx->cmd.u.xts.iv = &rctx->iv_sg;
 166         rctx->cmd.u.xts.iv_len = AES_BLOCK_SIZE;
 167         rctx->cmd.u.xts.src = req->src;
 168         rctx->cmd.u.xts.src_len = req->nbytes;
 169         rctx->cmd.u.xts.dst = req->dst;
 170
 171         ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);
 172
 173         return ret;
 174 }
 175
 176 static int ccp_aes_xts_encrypt(struct ablkcipher_request *req)
 177 {
 178         return ccp_aes_xts_crypt(req, 1);
 179 }
 180
 181 static int ccp_aes_xts_decrypt(struct ablkcipher_request *req)
 182 {
 183         return ccp_aes_xts_crypt(req, 0);
 184 }
 185
 186 static int ccp_aes_xts_cra_init(struct crypto_tfm *tfm)
 187 {
 188         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 189         struct crypto_ablkcipher *fallback_tfm;
 190
 191         ctx->complete = ccp_aes_xts_complete;
 192         ctx->u.aes.key_len = 0;
 193
 194         fallback_tfm = crypto_alloc_ablkcipher(tfm->__crt_alg->cra_name, 0,
 195                                                CRYPTO_ALG_ASYNC |
 196                                                CRYPTO_ALG_NEED_FALLBACK);
 197         if (IS_ERR(fallback_tfm)) {
 198                 pr_warn("could not load fallback driver %s\n",
 199                         tfm->__crt_alg->cra_name);
 200                 return PTR_ERR(fallback_tfm);
 201         }
 202         ctx->u.aes.tfm_ablkcipher = fallback_tfm;
 203
 204         tfm->crt_ablkcipher.reqsize = sizeof(struct ccp_aes_req_ctx) +
 205                                       fallback_tfm->base.crt_ablkcipher.reqsize;
 206
 207         return 0;
 208 }
 209
 210 static void ccp_aes_xts_cra_exit(struct crypto_tfm *tfm)
 211 {
 212         struct ccp_ctx *ctx = crypto_tfm_ctx(tfm);
 213
 214         if (ctx->u.aes.tfm_ablkcipher)
 215                 crypto_free_ablkcipher(ctx->u.aes.tfm_ablkcipher);
 216         ctx->u.aes.tfm_ablkcipher = NULL;
 217 }
 218
 219
 220 static int ccp_register_aes_xts_alg(struct list_head *head,
 221                                     const struct ccp_aes_xts_def *def)
 222 {
 223         struct ccp_crypto_ablkcipher_alg *ccp_alg;
 224         struct crypto_alg *alg;
 225         int ret;
 226
 227         ccp_alg = kzalloc(sizeof(*ccp_alg), GFP_KERNEL);
 228         if (!ccp_alg)
 229                 return -ENOMEM;
 230
 231         INIT_LIST_HEAD(&ccp_alg->entry);
 232
 233         alg = &ccp_alg->alg;
 234
 235         snprintf(alg->cra_name, CRYPTO_MAX_ALG_NAME, "%s", def->name);
 236         snprintf(alg->cra_driver_name, CRYPTO_MAX_ALG_NAME, "%s",
 237                  def->drv_name);
 238         alg->cra_flags = CRYPTO_ALG_TYPE_ABLKCIPHER | CRYPTO_ALG_ASYNC |
 239                          CRYPTO_ALG_KERN_DRIVER_ONLY |
 240                          CRYPTO_ALG_NEED_FALLBACK;
 241         alg->cra_blocksize = AES_BLOCK_SIZE;
 242         alg->cra_ctxsize = sizeof(struct ccp_ctx);
 243         alg->cra_priority = CCP_CRA_PRIORITY;
 244         alg->cra_type = &crypto_ablkcipher_type;
 245         alg->cra_ablkcipher.setkey = ccp_aes_xts_setkey;
 246         alg->cra_ablkcipher.encrypt = ccp_aes_xts_encrypt;
 247         alg->cra_ablkcipher.decrypt = ccp_aes_xts_decrypt;
 248         alg->cra_ablkcipher.min_keysize = AES_MIN_KEY_SIZE * 2;
 249         alg->cra_ablkcipher.max_keysize = AES_MAX_KEY_SIZE * 2;
 250         alg->cra_ablkcipher.ivsize = AES_BLOCK_SIZE;
 251         alg->cra_init = ccp_aes_xts_cra_init;
 252         alg->cra_exit = ccp_aes_xts_cra_exit;
 253         alg->cra_module = THIS_MODULE;
 254
 255         ret = crypto_register_alg(alg);
 256         if (ret) {
 257                 pr_err("%s ablkcipher algorithm registration error (%d)\n",
 258                         alg->cra_name, ret);
 259                 kfree(ccp_alg);
 260                 return ret;
 261         }
 262
 263         list_add(&ccp_alg->entry, head);
 264
 265         return 0;
 266 }
 267
 268 int ccp_register_aes_xts_algs(struct list_head *head)
 269 {
 270         int i, ret;
 271
 272         for (i = 0; i < ARRAY_SIZE(aes_xts_algs); i++) {
 273                 ret = ccp_register_aes_xts_alg(head, &aes_xts_algs[i]);
 274                 if (ret)
 275                         return ret;
 276         }
 277
 278         return 0;
 279 }